JBL and TQWT

[Ingvar Ahlberg]

Hi, new on this forum i hope i´m starting this thread in the right place.
After starting my audiolife around a pair of L100´s in the early 70´s and then comencing to horn design with JBL drivers i strayed into a lot of strange low efficiency systems, a long and sad story. A year ago the cat ate the foam edge surrounds of my RCF L12P48 bass units. Just prior to this i had got hold of a pair of unused 122A. I designed and put a TQWT design for these together and ended up with something closer to real life than anything i´ve heard. Really unbelievable bottom end extension (19 Hz in my livingroom), a little bit soft at the lowest octave maybe, perhaps a contribution from the Accuphase power amp driving the LF. Hf unit is a Heil AMT wich is ;imo; one of the best there is.
Just the other day i aquired two pristine D120 F units and started to think about a real JBL rock´n roll monitor. The idea is to design a TQWT for the D120´s and top it with my Alnico L75`s at around 5kHz, Finaly around at the question: is there anyone around here that has tried the D120 in a pipe? Horn would be the most obvious way, but then there is the WAF matter.

[johnaec]

TQWT ??

John

[matsj]

Tapered quarter wave tube.


Hallå ingvar ännu en svensk här

regards mats

[Ingvar Ahlberg]

TQWT ??
Hullo Mats, Swedes all over the place, as usual.
The TQWT sometimes refered to as Voight Horn, is not a horn but a sibling, a bastard so to speak in between horn and br. The beauty of TQWT is that You get allmost the efficiency gain of horn combined with lf extension on par with or surpassing br in an eenclosure only marginally larger than br. My 122A cabinets are a almost bookshelf-like measuring 110X55X34 cm and having a turnover at 19Hz, -3 is at 16,5 Hz,

[Flodstroem]

Hi Ingvar Ahlberg

is there anyone around here that has tried the D120 in a pipe?

My own project is not finished yet, its still in the "starting up mode", but I have done some calculations and Im still waiting for my new cone-kits to my 2215H (15" type LE15)

You should maybe be interested in reading the threads: (search for "Transmission Line" at this forum. Read the post "ML TQWT (what the h..k is that)"

Also I can tell you that Im a swede living in Norway
Regards

[Harryup]

Hej Ingvar,
whats the upper limits in frequency response? Picture?
Yes I'm a Swede too. Living in Stockholm.

Ha det bra
Bengt

[cecio]

Hi
do you still have the pair of RCF L12P48 ?
Do you want to sell them ?
Thank you